Comprehensive method for evaluating signalized intersections treatments: left turn prohibition and partial grade separation

Abstract

This research proposes a three-level project decision-making process taking into account the planning and screening, feasibility and performance study, and evaluation and decision-making in the development of an intersection improvement project. A planning and screening level is to quantify and compare the benefits and costs LTP and LCUP was developed to examine the potential applicability of these congestion mitigation actions by examining intersection delay using the Highway Capacity Manual 2010, accident frequency using the Highway Safety Manual, and cost-benefit analysis based on AASHTO's User Benefit Analysis for Highways Manual, prior to conducting extended data collection and detailed analysis. Feasibility and performance analysis is to examine the feasibility of a treatment by considering site-specific constraints, and if feasible, conduct detailed performance analysis using advanced analysis tools. Five-stage multiple attribute evaluation under uncertainty and fuzziness (MAFU) process is proposed in evaluation and decision-making level, which is able to assess the magnitudes of intersection treatment performance and to the fuzziness in stakeholder preference and the uncertainty in performance measurement. MAFU is designed to determinate the alternative which can best achieve a compromise between all competing objectives and conflicting interests. It features fuzzy mathematics (FAHP) to capture the stakeholder preferences, utility function theory (MAUT) to combine performance measures and describe risk sensitivity, and probabilistic approach (MCS) to model output uncertainties and conduct the tradeoff analysis. A case study is provided to demonstrate the application of this integrated and comprehensive method and the reliability of using this method for project evaluation and decision-making.